For a number of well-known reasons, ski boots comprise a rigid shell comprising a sole and a shell base surmounted by an upper which may or may not be articulated on the shell base. The upper and shell base may be composed of different separate elements, depending o various structure manufacturing methods.
These boots must meet at least two requirements: they must give the skier good performance by transmitting his orders as faithfully as possible to the ski; and they must also be comfortable. But the rigidity of the shell often makes it difficult, indeed painful, to put on and take off the boots. Very often, the shape imparted to the shell is preferably that of a closed boot, thereby requiring that the various components of the upper be separated, simultaneously if possible, an operation which is not always easily accomplished to allow the boot to be put on and taken off.